This is a multi-disciplinary program project, with research activities in the areas of gonorrhea and syphilis. Emphasis is on both basic microbiology and immunology, and applied problems such as organism identification and clinical epidemiology. Four integrated projects focus on the gonococcus, including basic genetics, biochemistry and antigenicity of the cell surface; virulence and host immune response; and importance of cell-wall deficient forms in human disease. Two integrated projects examine the basic physiology, pathogenicity, and immunology of T. pallidum.